Help with conversion

[clv101]

I've been thinking about electric bikes for a couple of years now, I've ridden a few, subscribe to A to B magazine and read the book. I've never owned or built one though. 'bout time that changed.

I'd like some help and advice choosing components and a suppler for a conversion kit. The donor bike is a 21" 2002 Kona Blast I've had since new, full spec on the link:

To start with the bike has a few issues; it needs a new headset, the forks have too much flex and the front hub is worn. However, it has recently had a new chain and cassette, new brake and gear cables and new pedals. I'm also planning to change to rigid forks.

The real questions are about the electric bike parts. I'm pretty much set on front wheel drive (mainly because the existing hub needs replacing anyway). As for requirements, range isn't that critical (~20 miles is okay) but I do want decent speed (at least 20mph on the flat) and as little drag from the motor as possible.

As far as I can tell I need, a brushless geared motor with clutch, a controller, a battery and some kind of throttle. Looking at various suppliers, UK based seems expensive unless anyone can show me otherwise so I've been looking at these two:

bmsbattery.com
emissions-free.com

Looking at BMS Battery, does this lot look reasonable?
BPM 36V350W Front Driving Bike Conversion Kit $179
36V 15Ah 40152S LiFePO4 Battery 12 Cells EBike Battery Pack $310
Alloy Shell 240W LiFePo4/Li-Ion/Lead Acid Battery EBike Charger $29.90
For a total of $518.90 (~£350)

What kind of speed will I get from that? It says it comes with a "A 450W 9Mosfets universal controller", 450W sounds good - but speed is more a function of voltage and the winding of the motor - how do I find out about that?

Looking at emissions-free, they have a kit called:
MXUS 36V 350W Geared Ebike Kit for $175 to which only a battery needs adding. Something like this: 39V 9.2Ah A123 Pack for $350 and a $55 charger. For a total of $580.

These setups seems approximately half the price of UK sellers - is there anyone in the UK able to supply similar for ~£400?

Has anyone here bought a kit from BMS Battery recently? Experiences?

I'm actually perfectly able to build my own wheels - so perhaps the best idea would be just to by the front hub motor bare? Would the saving be worth it once the cost of getting the right length spokes had been included? On BMS, the bare motor is only $46 cheaper than the whole kit!

Thanks for any assistance, the complexity of buying the kit has already delayed this project for over year!

 

[Cyclezee]

Hi clv101,

OK, Cyclezee can't compete with the price of the products you are considering, but we can compete when it comes to quality, performance and value for money. So please check out eZee kits here Bikes & Conversion Kits - Cyclezee Ltd.
We have the advantage of being UK based so you would not have any import costs or delivery charges and every eZee kit comes with a 2 year warranty.

Example of an eZee MTB Conversion​

Regards,

 

[JuicyBike]

Yep, Cyclezee's right. You will face import duty and vat on both the cost of the imported kit and also added to the cost of delivery.

If you don't like the kit when it finally arrives you can always send it back for a refund of course...

Or buy from the UK suppliers, Cyclezee, Xipi, JuicyBike, Oxygen, Wisper, Alien

If you really want an absolute bargain I will sell you a kit for one pound.

However it must be a pound that has been stolen from the begging bowl of a blind, homeless, begging, poet that has just sung you a poem that has reduced all who heard it to weeping tears of joy and gladness because of that poet's ability to convey the fundamentals of love, peace and happiness.

Now there's a bargain for you!

Please excuse the sarcasm, it's been a very long, hard day...

 

[JuicyBike]

You may find this old post useful...

 

[banbury frank]

Hi

I think Cyclezee can supply the 350 watt 20 mph kit for Off road use

Not Cheap But it will work and has full uk support And comes fully built in wheel

Order tomorrow and have the bike up and running in a few days

For Many years with UK support

You also have a good resale in UK supplies Kits

Frank

 

[clv101]

Thanks for your adverts, sorry, replies. I haven't been on the forum in a while and hadn't realised it had become such a marketing channel!

Do we have many builders in the UK who import their own components?

 

[Deleted member 4366]

Thanks for your adverts, sorry, replies. I haven't been on the forum in a while and hadn't realised it had become such a marketing channel!

Do we have many builders in the UK who import their own components?

We get your question asked quite frequently on this forum and to be honest it's quite difficult to answer because there's lots of ifs and buts. I'll give you some of my thoughts:

Your bike's brakes might require upgrading to disks because of the extra weight of the kit. Headset bearings are not difficult to replace. You need to change the forks anyway, so while you're at it, drop in a new headset. Scotty just got a nice set of Manitou forks for £40 and they look very strong for a front motor. Front suspension helps a lot with comfort.

The kit you mentioned from BMS battery won't give you 20mph because the motor is a slow wind (201rpm). There are other versions of this motor that go faster, but BMS battery don't do them. They're coded with a wheel diameter and a number that denotes the speed. You need a code 13 or lower. The 201rpm is code 15 and will give about 18mph at 36v and is better for hill-climbing than speed. Running the code 15 at 48v will give you the speed. The 9FET controller doesn't know how fast you're going. It just provides current to the motor. Speed is dependent on the motor. You need 20 to 25amps for 20mph depending on how hard you pedal and whether you want to sustain speed on slight hills and wind. The 9 FET can do that easily.

The MXUS motor doesn't have a particularly good reputation on the ES forum. I've never tried one and I've not heard of specific problems, but you could search on that forum for more info about it. They would recommend the MAC or BPM as the minimum for your requirements. There's also the Cute motor, but I've not heard any reports on the more powerful ones. I've got a 250w one, which seems OK, but definitely not built as strong as the equivalent Bafang.

If you're thinking of 20mph continuous for 20 miles, even a 15aH battery is marginal unless you want to pedal hard at the same time. With a 350w motor and a 15 or 20aH battery, you've added quite a lot of weight to your bike as well.

For a 350w motor with power to do 20mph, you'll need to re-inforce the fork drop-outs unless they're strong steel ones. This means fabricating something out of steel plate or buying ready-made ones at about £50 a pair.

The Bafang 250w motors might also be suitable if you like to pedal quite hard. They're not suitable if you want a sustained 20mph without pedalling.

When you buy stuff direct from China, there's a chance that you'll get hit for duty. Rough guess: 50% chance you wont have to pay; 40% chance you'll pay £20 to £30; 10% chance pay about £100.

The Ezee and I think the Xipi kit both come with drop-out re-inforcers, which saves a lot of messing about. The Ezee kit is more or less plug-and-play and I believe can give the speed that you want (check with Cyclezee first) but you'll probably need the more expensive 14aH battery. The Xipi kit is direct drive, so not so good on the free-wheel front.

In summary:
If you like to pedal hard, you could get 18 to 20mph out of a 36v 250w motor with 48v and a controller that can give about 17 or 18 amps.
The 36v BPM kit with 48v will do it easily but you'll need at least 12aH battery
The Ezee kit with the 14aH battery, although more expensive can also do it and would be much easier to fit. Make sure that you tell them you want 20mph when ordering.
There's probably other ways of doing it as well, but I've no experience of them.

 

[banbury frank]

Hi clv101 and welcome back to the forum

There is now A flourishing Kit and finished Ebike market in the UK

We all try and work with each other to Grow the Ebike market and give Advice and help on problems with repairs and supply's

Frank